It came after Nikki woke up in a coffin in the last episode, while Jack tried to find her in time.

The brave expert managed to save 20 other hostages before almost meeting her own end.
Realising he didn’t have much time, Jack said: “She shouldn’t still be breathing, meaning she had time to make her escape.”

Nikki was later seen bursting out of a casket, which ended up being in an ancient burial site rather than actually underground.